Although few in number, there are existing systems for testing attenuators, but they are usually very limited in capability, speed (throughput), repeatability, and traceability (for example to NBS standards). Common limitations of currently available attenuator testers include the following: limited frequency range of operation (band-limited), lack of dynamic range required to accurately measure large value attenuators (greater than about 80 dB), relatively slow and encumbered testing in view of the use of bridges for SWR (Standing Wave Ratio) testing, results lack measurement repeatability due to connector and switch repeatability (especially at higher frequency), and results lack traceability of accuracy to known standards.